A.W. Visser

The relative contribution of mechanical stress and systemic processes in different types of osteoarthritis: the NEO study

Objective To study the relative contribution of surrogates for mechanical stress and systemic processes with osteoarthritis (OA) in weight-bearing and non-weight-bearing joints. Methods The Netherlands Epidemiology of Obesity study is a population-based cohort including 6673 participants (range 45–65 years, 56% women, median body mass index 26 kg/m2). Weight (kg) and fat mass (kg) were measured, fat-free mass (kg) was calculated. The metabolic syndrome was defined following the Adult Treatment Panel III criteria. Knee and hand OA were defined according to the American College of Rheumatology clinical criteria. Logistic regression analyses were performed to associate surrogates for mechanical stress (such as weight, fat-free mass) and systemic processes (such as metabolic syndrome) with OA in knees alone, knees and hands or hands alone, adjusted for age, sex, height, smoking, education and ethnicity, and when appropriate for metabolic factors and weight. Results Knee, knee and hand, and hand OA were present in 10%, 4% and 8% of the participants, respectively. Knee OA was associated with weight and fat-free mass, adjusted for metabolic factors (OR 1.49 (95% CI 1.32 to 1.68) and 2.05 (1.60 to 2.62), respectively). Similar results were found for OA in knees and hands (OR 1.51 (95% CI 1.29 to 1.78) and 2.17 (95% CI 1.52 to 3.10) respectively). Hand OA was associated with the metabolic syndrome, adjusted for weight (OR 1.46 (95% CI 1.06 to 2.02)). Conclusions In knee OA, whether or not in co-occurrence with hand OA, surrogates for mechanical stress are suggested to be the most important risk factors, whereas in hand OA alone, surrogates for systemic processes are the most important risk factors.

Degree of synovitis on MRI by comprehensive whole knee semi-quantitative scoring method correlates with histologic and macroscopic features of synovial tissue inflammation in knee osteoarthritis

OBJECTIVE To evaluate the association between synovitis on contrast enhanced (CE) MRI with microscopic and macroscopic features of synovial tissue inflammation. METHOD Forty-one patients (mean age 60 years, 61% women) with symptomatic radiographic knee OA were studied: twenty underwent arthroscopy (macroscopic features were scored (0-4), synovial biopsies obtained), twenty-one underwent arthroplasty (synovial tissues were collected). After haematoxylin and eosin staining, the lining cell layer, synovial stroma and inflammatory infiltrate of synovial tissues were scored (0-3). T1-weighted CE-MRIs (3 T) were used to semi-quantitatively score synovitis at 11 sites (0-22) according to Guermazi et al. Spearmans rank correlations were calculated. RESULTS The mean (SD) MRI synovitis score was 8.0 (3.7) and the total histology grade was 2.5 (1.6). Median (range) scores of macroscopic features were 2 (1-3) for neovascularization, 1 (0-3) for hyperplasia, 2 (0-4) for villi and 2 (0-3) for fibrin deposits. The MRI synovitis score was significantly correlated with total histology grade [r = 0.6], as well as with lining cell layer [r = 0.4], stroma [r = 0.3] and inflammatory infiltrate [r = 0.5] grades. Moreover, MRI synovitis score was also significantly correlated with macroscopic neovascularization [r = 0.6], hyperplasia [r = 0.6] and villi [r = 0.6], but not with fibrin [r = 0.3]. CONCLUSION Synovitis severity on CE-MRI assessed by a new whole knee scoring system by Guermazi et al. is a valid, non-invasive method to determine synovitis as it is significantly correlated with both macroscopic and microscopic features of synovitis in knee OA patients.

Association of pain in knee osteoarthritis with distinct patterns of synovitis

To determine possible patterns of synovitis on contrast‐enhanced magnetic resonance imaging (CE‐MRI) and its relation to pain and severity in patients with radiographic knee osteoarthritis (OA).

The role of fat mass and skeletal muscle mass in knee osteoarthritis is different for men and women: the NEO study

OBJECTIVE To investigate if the amount of fat mass (FM) or skeletal muscle mass (SMM) is more strongly associated with knee osteoarthritis (OA), in both men and women. METHODS The Netherlands Epidemiology of Obesity (NEO) study is a population-based cohort aged 45-65 years, including 5313 participants (53% female, median body mass index (BMI) 29.9 kg/m(2)). FM (kg), fat percentage, SMM (kg) and skeletal muscle (SM) percentage were estimated using bioelectrical impedance analysis (BIA). Clinical OA was defined following the ACR criteria. Structural OA was defined based on magnetic resonance imaging (MRI) in 1142 participants. Logistic regression analyses were used to examine the associations of all body composition measures with clinical and structural knee OA per standard deviation (SD), stratified by sex and adjusted for age and height. RESULTS Clinical or structural OA was present in 25% and 14% of women and 12% and 13% of men, respectively. FM and fat percentage were positively associated with clinical knee OA in men and women. SMM was positively associated, while the SM percentage was negatively associated with clinical OA in both men and women. The FM/SMM ratio was positively associated with clinical OA. All determinants showed even stronger ORs for structural knee OA. In men, SMM was more strongly associated with knee OA as compared to FM whereas in women, FM was most strongly associated. CONCLUSION Especially a high FM/SMM ratio seems to be unfavorable in knee OA. In men, SMM is most strongly associated with knee OA whereas in women FM seems to be of most importance.

Radiographic scoring methods in hand osteoarthritis – a systematic literature search and descriptive review

OBJECTIVE This systematic literature review aimed to evaluate the use of conventional radiography (CR) in hand osteoarthritis (OA) and to assess the metric properties of the different radiographic scoring methods. DESIGN Medical literature databases up to November 2013 were systematically reviewed for studies reporting on radiographic scoring of structural damage in hand OA. The use and metric properties of the scoring methods, including discrimination (reliability, sensitivity to change), feasibility and validity, were evaluated. RESULTS Of the 48 included studies, 10 provided data on reliability, 11 on sensitivity to change, four on feasibility and 36 on validity of radiographic scoring methods. Thirteen different scoring methods have been used in studies evaluating radiographic hand OA. The number of examined joints differed extensively and the obtained scores were analyzed in various ways. The reliability of the assessed radiographic scoring methods was good for all evaluated scoring methods, for both cross-sectional and longitudinal radiographic scoring. The responsiveness to change was similar for all evaluated scoring methods. There were no major differences in feasibility between the evaluated scoring methods, although the evidence was limited. There was limited knowledge about the validity of radiographic OA findings compared with clinical nodules and deformities, whereas there was better evidence for an association between radiographic findings and symptoms and hand function. CONCLUSIONS Several radiographic scoring methods are used in hand OA literature. To enhance comparability across studies in hand OA, consensus has to be reached on a preferred scoring method, the examined joints and the used presentation of data.

Degree of synovitis on MRI is correlated with histological and macroscopic features of synovial tissue inflammation in knee osteoarthritis

Background and objectives Synovitis is often present on MRI of OA knees and is an important determinant of pain. To better understand the nature of synovitis seen on MRI the authors compared microscopic and macroscopic features of synovial tissue inflammation with synovitis grade on contrast enhanced (CE) MRI. Methods and methods Twenty-two patients (mean age 61±7 years, 73% women, mean BMI 30±5 kg/mm2) with symptomatic radiographic knee OA attending the rheumatology outpatient clinic were included. Arthroscopy of the index knee was performed and macroscopic features (neovascularisation, villi, fibrin and hyperplasia) were scored (0–4). Furthermore, 15–20 synovial biopsies per knee were obtained. After H&E staining, synovial tissue samples were microscopically scored on features: synovial lining layer hyperplasia/enlargement, activation of resident cells/stroma and degree of inflammatory infiltrates. Each feature was scored from 0–3 and a total sum score per patient was devised. Mean total scores (0–9) by three observers were used. Saggital and axial T1-weighted CE MRI images (3T) were used to semi quantitatively score synovitis at 11 different sites according to Guermazi et al, ranging from 0–22.1 Self reported pain was assessed by visual analogue scale (VAS, 0–100). Pearson correlations adjusted for age were used for correlation between total histology synovitis score and total MRI score. Spearman ρ correlations were used for correlation between total histology score and macroscopic features. Both were calculated by SPSS 16.0. Results The mean (SD) synovitis score on MRI was 7.8 (3.9), representing a mild synovitis and mean (SD) histology score was 2.1 (1.5). Median (range) score of macroscopic features (0–4) were 2.0 (1.0–4.0) for neovascularisation, 1.0 (0.0–3.0) for hyperplasia, 2.0 (0.0–4.0) for villi and 2.0 (0.0–3.0) for fibrin. Synovitis score on MRI correlated significantly with microscopic synovitis score (r=0.5, p=0.019] and macroscopic neovascularisation score (r=0.6, p=0.002) and hyperplasia (r=0.4, p=0.40). Furthermore statistically significant correlation between microscopic synovitis score and macroscopic neovascularisation (r=0.5, p=0.012) existed. No significant correlations with VAS pain were seen. Conclusions Synovitis severity on T1 weighted CE MRI images is significantly correlated with both macroscopic and microscopic features of synovitis in patients with knee OA. No association with severity of pain was seen. Therefore, CE MRI evaluation is a reliable, non invasive way to determine synovitis severity in OA patients.

Bakers' cyst and tibiofemoral abnormalities are more distinctive MRI features of symptomatic osteoarthritis than patellofemoral abnormalities

Objective To investigate which structural MR abnormalities discriminate symptomatic knee osteoarthritis (OA), taking co-occurrence of abnormalities in all compartments into account. Methods The Netherlands Epidemiology of Obesity (NEO) study is a population-based cohort aged 45–65 years. In 1285 participants (median age 56 years, 55% women, median body mass index (BMI) 30 kg/m2), MRI of the right knee were obtained. Structural abnormalities (osteophytes, cartilage loss, bone marrow lesions (BMLs), subchondral cysts, meniscal abnormalities, effusion, Bakers cyst) at 9 patellofemoral and tibiofemoral locations were scored following the knee OA scoring system. Symptomatic OA in the imaged knee was defined following the American College of Rheumatology criteria. Logistic ridge regression analyses were used to investigate which structural abnormalities discriminate best between individuals with and without symptomatic OA, crude and adjusted for age, sex and BMI. Results Symptomatic knee OA was present in 177 individuals. Structural MR abnormalities were highly frequent both in individuals with OA and in those without. Bakers cysts showed the highest adjusted regression coefficient (0.293) for presence of symptomatic OA, followed by osteophytes and BMLs in the medial tibiofemoral compartment (0.185–0.279), osteophytes in the medial trochlear facet (0.262) and effusion (0.197). Conclusions Bakers cysts discriminate best between individuals with and without symptomatic knee OA. Structural MR abnormalities, especially in the medial side of the tibiofemoral joint and effusion, add further in discriminating symptomatic OA. Bakers cysts may present as a target for treatment.

OP0025 Different Patterns of Synovitis Present in OA Patients Associate Differentially with Pain

Background Synovitis is prevalent in knee OA and is an important determinant of pain. Objectives To better understand the nature of synovitis and its association with pain we investigated patterns of synovitis on contrast enhanced (CE) MRI and its relation to pain and radiographic severity. Methods 91 patients (mean (SD) age 62 (7.5) years, 68% woman, BMI median (IQR) 29 (26-31) kg/mm2, median (IQR) Kellgren-Lawrence score 3 (2-4)) with symptomatic knee OA attending the rheumatology or orthopedic outpatient clinic were included. 55 patients underwent arthroscopy and 36 arthroplasty. Sagittal and axial T1-weighted CE MRI images (3T) were used to semi-quantitatively score synovitis at 11 sites (total range 0-22) according to Guermazi et al.1 (Ann Rheum Dis 2011). Self-reported pain was assessed by visual analogue scale (VAS, 0-100), knee injury and osteoarthritis outcome score (KOOS (subscale pain),0-100) and measure of intermittent and constant osteoarthritis pain (ICOAP, intermittent pain (0-100), constant pain (0-100)). Principal component analysis (PCA) with varimax rotation and Keiser Normalization was used to investigate patterns of synovitis for all patients. A factor was said to load significantly on a component when loading exceeded 0.4. Subsequently, different patterns were associated with pain measures in linear regression analysis adjusted for gender and age using SPSS 20.0. Log transformations were used when appropriate. Results A mild synovitis was observed (median (IQR) 7.0 (5-10)). Mean (SD) KOOS pain was 51.8 (23.3). Median (IQR) VAS was 53.0 (32-70) and ICOAP constant pain 35.0 (15.0-55.0) and ICOAP intermittent pain 45.8 (25-60.4). PCA resulted in extraction of 3 components (Eigen value > 1), together explaining 53.7% of variance. Component 1 was characterized by synovitis at 7 sites with mainly medial parapatellar involvement associated with KOOS pain, ICOAP constant pain and radiographic severity, not with VAS and ICOAP intermittent pain. Component 2 was characterized by synovitis at site adjacent to the anterior cruciate ligament, medial parameniscal site, intercondylar site and suprapatellar site, but did not associate with any of the pain measures nor with radiographic severity. Component 3, characterized by synovitis at 3 sites (mainly characterized by synovitis loose body site), was also associated with radiographic severity. Conclusions Different patterns of synovitis in knee OA were observed. Our results suggest that a certain synovitis pattern is associated with pain, providing important insights into mechanisms underlying osteoarthritic knee pain. References Guermazi A, Roemer FW, Hayashi D, Crema MD, Niu J, Zhang Y et al. Assessment of synovitis with contrast-enhanced MRI using a whole-joint semiquantitative scoring system in people with, or at high risk of, knee osteoarthritis: the MOST study. Ann Rheum Dis 2011;70:805-11. Disclosure of Interest None Declared

258 PAIN AND FUNCTIONAL DISABILITY IN SYMPTOMATIC HAND OSTEOARTHRITIS DEPEND ON TYPE OF JOINT INVOLVEMENT

Purpose: Pain, a core outcome in osteoarthritis (OA) research, can be measured during physical examination by an articular index called the Doyle Index. The value of this pain score as an outcome measure in OA is not established. In the present study the reliability, validity and feasibility of this index will be determined. Methods: The Doyle Index includes 48 joints or joint groups, being hands, wrists, elbows, shoulders, acromioclavicular, sternoclavicular, hips, knees, ankles, feet and spine. Pain is assessed by pressure on the joint margin or by passive movement of the joint, scored on a four-point scale (0 = no pain, 1 = pain, 2 = pain and wincing, 3 = pain, wincing and withdrawal of the joint; range 0–144). The Doyle Index was performed by one observer in 90 patients with OA at multiple joint sites in the hands or with OA in two or more of the following joint sites: hand, knee, hip, cervical or lumbar spine. Reliability and feasibility were determined in a random sample of 18 patients, by examining these patients twice with a 90 minutes time interval, using four observers. Intraclass correlation coefficients (ICC) and their 95% confidence intervals (95%CI) were calculated, as well as the mean time it took each observer to perform the Doyle Index. Validity was assessed by correlating Doyle Index scores obtained in the whole population to the pain subscale scores of the Australian/Canadian Osteoarthritis Hand Index (AUSCAN) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), using Spearman rank coefficient. Results: The patient population consisted of 90 patients (82% women, mean age 65.0 years). The median Doyle Index score for the whole population was 9.5 (interquartile range (IQR) 4−16). The median score of all observations in the sample of 18 patients was 16.5 (IQR 8.25−29.75). Interobserver reliability was 0.88 (95% CI 0.77−0.94). Intraobserver reliabilities for the four observers ranged from 0.94 (95% CI 0.84−0.98) to 0.97 (95% CI 0.93−0.99). The mean time to perform the Doyle Index for a single patient was between 4.0 and 6.0 minutes. The Doyle Index scores correlated to the AUSCAN pain subscale (r = 0.48 (p< 0.001)) and to the WOMAC pain subscale (r = 0.45 (p< 0.001)). Conclusions: The Doyle Index showed to be a reliable, valid and feasible measure for the assessment of OA pain during physical examination. Based on the findings of the present study, the Doyle Index is a promising outcome measure for pain in OA, although further research on its clinimetric properties is advisable.